A 'mind-blowing' swim for survival and complex abdomen reconstruction saved Sam after Thursday Island shark attack

The last thing Sam Nai remembers before the shark attacked is eating a mango in a dinghy.

Warning: This story contains graphic details that some readers may find confronting.

As he often did, he spent a Saturday afternoon in October last year at Quarantine Wharf, on Thursday Island in the Torres Strait, fishing and swimming with two friends.

When they jumped into the sea, a shark bit into his abdomen, exposing his organs and leaving him fighting for his life.

After more than five months at the Townsville University Hospital where he underwent a complex abdominal reconstruction, Sam, now 15, is finally home.

His survival has been described as extraordinary, and it is believed Sam's case may be the most extensive shark bite injury ever survived by a patient documented in medical literature.

An island emergency

On October 11, 2025, Shanna Mosby was at home when a neighbour ran to tell her that her son was in trouble.

She drove to the wharf, calling family and an ambulance for help.

"When I arrived I just screamed out to Sam. I screamed his name," she said.

The shark had taken a large section of his flank.

She took a shirt from her nephew and used it to wrap up Sam in a bid to hold in his organs.

Despite the extent of the wound, Ms Mosby said there was little blood.

"He was squeezing my hands and he was saying he's in pain, and I'm like, 'Pain is a good thing, bubba. Pain is a good thing,'" she said.

As nearby residents came to help, they took the floorboard out of a dinghy to make a stretcher.

Within 15 minutes, Sam was in an ambulance. After four hours of treatment by a local team on Thursday Island, he was stabilised and put on a helicopter to Horn Island and then a plane to Townsville.

As Ms Mosby watched the in-flight doctors and nurses treat her son, she counted the bags of blood he received — a total of six — and thought about how he would survive.

"Never once did it cross my mind that I would lose my son. It was just recovery and [how] things are going to be different," she said.

"Different is OK. Different is not good. Different is not bad. Just different. I can do different."

Survival by a millimetre

Paediatric surgeon Brendan O'Connor led Sam's treatment from the night of the attack.

When the teenager arrived at the Townsville University Hospital, Dr O'Connor said doctors feared he had lost a kidney and may have suffered significant organ damage.

"He had very extensive tissue loss. Loss of skin, fat, muscle from the left side of his body basically," Dr O'Connor said.

A CT scan showed that the shark's teeth had left his organs unscathed, a "huge relief" for Ms Mosby and a "pleasant surprise" for the medical team.

"A millimetre further and the bowel would have been injured as well, which would have been a much more significant problem for Sam," Dr O'Connor said.

The bite had however grazed his hip bone.

The first step was emergency surgery to clean the massive wound and close his peritoneum — the belly lining.

"Amazingly, he didn't get any infection," Dr O'Connor said.

A painstaking reconstruction

For the next few weeks while in the intensive care unit, Sam received weekly dressing changes as his surgical team planned the reconstruction of his abdomen.

Given how much tissue had been lost, Dr O'Connor said they decided to rebuild his abdomen using a synthetic dermis substitute called a "biodegradable temporizing matrix".

Often used for burn victims, it is put on in layers allowing blood vessels and tissue to grow through it, eventually rebuilding tissue.

It meant they were able to avoid taking muscle 'flaps' from other parts of Sam's body to use as grafts.

"[It] was working so well that we were able to get even more than that 3 or 4 millimetres of thickness without having to sacrifice the muscle from the other side of his chest," Dr O'Connor said.

They also installed a permanent mesh to provide structure and skin grafts to close the wound.

Dr O'Connor said after consulting the Australian Shark Incident Database and other medical literature, he believes Sam's injury was the most extensive shark bite injury ever recorded where a patient has survived.

"There has never been a report of someone who has had such significant tissue loss on their trunk, on their tummy, lower chest and on their flank, which is what makes the case particularly unique," he said.

Shark bites rare

Shark expert Dr Daryl McPhee, from Bond University, said fatal shark bites and serious injuries were caused by white sharks, bull sharks and tiger sharks.

It is likely that a bull shark or tiger shark bit Sam.

"There are a lot of shark species that occur in the Torres Strait — whilst there are some historical sites [of bites] they are thankfully rare," Dr McPhee said.

He said most shark bites happened to the legs and the arms, as most people bitten are surfing or swimming on the top of the water.

He said that given the likelihood of significant blood loss from a shark bite, it was rare for someone to survive a significant bite to the torso.

"Besides blood loss, an issue that can occur is secondary infections," he said.

"The ocean is full of various forms of marine bacteria."

He said it was important to remember that given the number of people who use the ocean every day, bites are still very rare.

"However, such statistics are of no comfort to the friends and families of the victims of fatal bites," he said.

'Grit and determination'

Dr O'Connor said Sam's survival could be attributed not just to his young age, but also his strength and the support of his mum.

He said it was "mind-blowing" Sam was able to swim the estimated 20 metres back to shore after the bite.

"It's amazing he was able to show so much grit and determination and such a will to survive" Dr O'Connor said.

It was the same determination he showed throughout his recovery.

After four weeks in hospital, he stood and walked again for the first time since the attack.

With regular physio sessions he has built up his strength — first using a frame, later moving on crutches and finally walking unaided.

"He's such a tough guy. He had four solid months of at least weekly trips to the operating theatre." Dr O'Connor said.

Ms Mosby said while it was difficult to watch Sam's slow recovery, she gained hope as he began to show glimpses of his normal personality.

"Seeing his eyes light up, I was like 'oh there's my Sam'. Watching him push through, watching him battle every day and watching his spirit thrive," she said.

When he began to argue again, she knew he was back.

"To have that first argument from him being sick to being well enough to have a go at me … Oh, that's my baby. There he is," she said.

"He's my extrovert, he's bubbly, fearless. He's brave."

And while it may be expected that someone who had survived such a trauma would avoid the ocean in the future, Ms Mosby hopes that Sam can live with it, just the way he did before.

Together, they've even researched sharks — watching videos and reading articles.

"Growing up on the island we don't teach our children to fear the environment. You adapt, you change, you respect," Ms Mosby said.

And while Sam said he feels lucky to have survived, knowing that many people do not, he feels strong again.

"It's like a new me," Sam said.